The grounding order won’t be lifted until the plane is proved to be safe, the FAA has said. Boeing has said it has hundreds of engineers working around the clock to resolve the issue as quickly as possible.

A Boeing electrical-systems engineer, who asked for anonymity, said different teams are working on “multiple fixes,” the most basic of which is a more robust containment box for the lithium-ion batteries that malfunctioned.

The Wall Street Journal quoted government and industry officials Wednesday as saying Boeing is also looking at increasing the separation between cells in the batteries, to reduce the potential threat of heat spreading from cell to cell, and at adding enhanced heat-sensors to provide better warning of unusual overheating.

The Journal said Boeing is also considering ways to keep cells more rigid, preventing them from shifting under certain conditions and interfering with electronics.

“There is an increasing concern that this could take longer than earlier anticipated,” said Michel Merluzeau, a consultant with G2 Solutions in Kirkland.

“Boeing’s proposed solution to build a containment around the battery should certainly help and adds an extra layer of safety in the unlikely event of another battery malfunction,” he said. “It however is only part of the solution which should include permanently resolving the root cause of the problems experienced by the 787 electrical system.”

For Thursday’s ferry flight, the crew will have to perform “a number of inspections to verify that the batteries and cables show no signs of damage,” the FAA said.

They will also be required to check for specific status messages that could indicate problems, both before and during the flight, and will have to land immediately if one occurs, the agency said.

“While our work to determine the cause of the recent battery incidents continues in coordination with appropriate regulatory authorities and investigation agencies, we are confident — as is the FAA — that the 787 is safe to operate for this activity,” said Marc Birtel, a spokesman at Boeing’s commercial headquarters in Seattle. “Safety of the crew on board is our top priority.”

Japan’s All Nippon Airways (ANA) — the launch customer for the Dreamliner and the largest operator of the plane so far — said Wednesday it canceled all domestic and international flights scheduled to use the new model through March 30.

That means 1,887 ANA flights are being canceled between the Jan. 16 grounding and March 30, affecting more than 126,000 passengers, the Tokyo-based carrier said.

In the U.S., United Airlines said it is taking the 787 out of its flying plans for the rest of this month.

United says it has replaced its six 787s with other planes. Airline spokeswoman Megan McCarthy told The Associated Press the plane swaps include new flights from Houston to Lagos, Nigeria, which were supposed to switch to a 787 in late January.

She said United still plans to start new flights from Denver to Tokyo’s Narita airport March 31.

The NTSB will give another detailed briefing Thursday on its investigation into the Jan. 16 battery fire on a 787 parked at Logan airport in Boston.

In an interview Wednesday, NTSB chief Deborah Hersman said investigators are looking at each of the cells used in the 787’s lithium-ion battery, the three windings in each of the cells and the component parts. That includes tests on examples of the batteries used in the jet.

The safety board is looking at “the macro level to the microscopic level on this battery,” Hersman said. The board has evidence of short circuits in cells of the battery, “thermal runaway” and an uncontrolled chain reaction, she said.

“Those features are not what we would have expected to see in a brand-new battery on a brand-new airplane,” Hersman said. “We want to make sure the design is robust and the oversight of the manufacturing process is adequate.”

Boeing said last week it’s continuing to produce 787s at a rate of five a month, ramping up to 10 a month by year-end, and is still working on the development of two bigger versions of the jet.

The plane is the world’s first composite-plastic airliner and the first to use new electrical systems to help save on fuel.

It was three and a half years behind when it entered service with ANA in late 2011, after Boeing struggled with the new materials and manufacturing processes.

The company has delivered 50 of the planes so far to eight airlines around the world and has orders for another 800.

Information from Seattle Times aerospace reporter Dominic Gates is included in this report.